Method for installing subsoil moisture barrier

ABSTRACT

A METHOD OF INSTALLING A SUBSOIL MOSITURE BARRIER OF WATER-IMPERVIOUS PLASTIC MATERIAL IS DISCLOSED WITH APPARATUS FOR ITS CONTINUOUS INSTALLATION.

Nov. 9., 1971 D. o. HANSON 3,613,329

METHOD FOR INSTALLING SUBSOIL MOISTURE BARRIER Filed Aug. 19, 1969 I2 IO l3 [7 14 SI q 1 (I Q o I I l l l l I I I 30 20 I l 2| I I 22 i F I ll I 1%] I I I% 7 T T1 HH INVENTOR.

D. O. HANSON FIG.

ATTOR EYS United States Patent 3,618,329 METHOD FOR INSTALLING SUBSOIL MOISTURE BARRIER Donald O. Hanson, Bartlesville, Okla., assiguor to Phillips Petroleum Company Filed Aug. 19, 1969, Ser. No. 851,397 Int. Cl. E02f /10; E03b N00 US. Cl. 6172.6 4 Claims ABSTRACT OF THE DISCLOSURE A method of installing a subsoil moisture barrier of water-impervious plastic material is disclosed with apparatus for its continuous installation.

This invention relates to a method and apparatus for establishing an underground moisture barrier.

In one of its more specific aspects, this invention relates to a method of placing a moisture barrier film beneath the surface of the soil and to mobile apparatus for placing the moisture barrier.

The positioning of barriers at optimum subsurface depths for the retention of moisture thereabove and the resulting agronomical benefits are well known. Generally such barriers comprise a series of continuous flexible membranes substantially impervious to water, adjacently positioned, these membranes preventing the rapid loss of water from that soil above the membrane.

It has been shown that the installation of the barriers must be made at considerable depth below the surface rather than immediately below the surface. Hence, in installing the barriers, considerable excavation of soil is required with the result that the weight of soil upon placement upon the membrane often dislocates the membrane from its intended position with the result that the continuous and impervious character of the membrane is destroyed and the installation is less than fully effective. The method and apparatus of this invention are directed toward remedying those defects of the prior art.

According to the method of this invention a first excavation is formed and there is deposited substantially across its width a substantially water-impervious membrane, having at least one upstanding sidewall. The soil removed in forming the first excavation is deposited over a portion of the first membrane to leave one of its edges exposed, and there is formed at least a second excavation laterally contiguous with the first excavation and into which is placed a membrane in lateral contact with that exposed edge of the membrane disposed in the previously formed excavation. The last deposited membrane has one of its edges in upstanding position. After the deposition of the final membrane, the excavation is closed.

The apparatus of this invention contemplates a mobile vehicle equipped with a forwardly positioned excavating means, an intermediately positioned barrier positioning means and a rearwardly positioned distributing means, that material removed by the excavating means being transferred by transfer means to the distributing means after positioning of the barrier in the excavation by the barrier positioning means.

Accordingly, it is an object of this invention to provide a method for installing an improved underground water barrier.

It is another object of this invention to provide apparatus for installing an improved underground water barrier.

Any material suitable for the establishment of a waterimpervious barrier can be employed. Such materials include water-impervious materials such as asphalts, asphalt emulsions and the like, spray deposited in the excavation. Suitable materials also include continuous filaments such as polymeric sheet materials deposited in overlapping contactual relationships, or any combination of such sheet materials and such asphaltic materials.

The method of this invention will be described, without meaning to limit the invention thereto, with reference to the deposition of a water-impervious membrane in a channel in a series of individually deposited sheets, widthwise contiguous in that each sheet after deposition has superimposed on it that material excavated in the formation of the channel in a first deposition which leaves one edge of the sheet exposed and having the remainder of its surface covered after its exposed edge is placed in contact with the next deposited sheet, the sheets being deposited at a substantially uniform elevation across their breadth and along their length. This latter feature is important inasmuch as membranes deposited in a trough configuration along either of their principal dimensions have been found to produce alternate paths of vegitated and nonvegitated areas due to variations in the extent of moisture retention or accumulation over their surfaces.

The description of this invention will be facilitated when made in conjunction with the attached drawings of which FIG. 1 is an end elevational view of the apparatus of this invention in operation.

FIG. 2 is a side elevational view of the apparatus of this invention taken through section 22 of FIG. 1.

FIG. 3 is an end elevational view of membranes as deposited and within the unfilled excavations.

Referring now to FIG. 1, there is shown mobile vehicular excavator 1 for producing the excavation. The vehicle is supported on wheels 2 sufficiently spaced to span the excavation, a film carrier or barrier roll 3 mounted on and adapted for movement along shaft 5 by means of positioning bar 6 for dispensing the film.

As shown in FIG. 2, excavator 1 is also provided with excavating means 7 such as a bucket chain, a rotary digger, and the like, which transfers the excavated mate rial onto continuous belt 8 which discharges onto positionable chute 9 which discharges, optionally, toward one or the other side of excavator 1. Positioned beneath excavator 1 is spring-loaded roller 4 adapted to travel along the bottom of excavated trough and to smooth and compress the soil remaining in the excavation formed by excavation means 7.

Referring now to FIG. 3, there is shown the paths of the excavation and the corresponding paths of membrane placement and soil placement as made by the excavator. It will be seen that the film will be somewhat greater in width than the width of the excavation into which it is deposited, the extra width being substantially equal to the width of the overlap. Generally an overlapping width of from about 2 to about 4 inches has been found suitable.

With reference to FIG. 3, and assuming that excavator 1 is moving away from the reader and into the view, the first excavation extends from point 10 to 11; thereafter membrane 30 is positioned in the excavation so that membrane 30 is displaced to one side of the excavation in the first excavation and occupies position 10 to 11. For this purpose, as applicable only to the first and last of the membranes deposited, membrane 30 has its one edge turned upwardly to conform to the configuration of the excavation and to act as a lateral moisture barrier.

After placement of membrane 30, that excavated soil, having been carried by continuous belt 8 from excavating means 7 to chute 9, is deposited from chute 9 from point 12 to point 13, leaving that edge 13-11 of the membrane exposed. Having passed to the end of the area desired to be excavated, excavator 1 turns and begins traveling in a direction toward the reader and out of the view of FIG. 3. Thereupon, film carrier 3 is slidably positioned along shaft by means of positioning bar 6 to discharge to the opposite side of excavator 1 and chute 9 is positioned to discharge to the opposite side of excavator 1.

As a result, the path of the second excavation, as shown in FIG. 3, is from point 11 to point 14, the position of the second membrane placement is from point to 14 and the path of the second soil replacement is from 13 to 17, leaving edge 17-14 of the second membrane available for overlapping by the third membrane 21-22.

Prior to the positioning of any membrane within the excavation, spring loaded roller 4 is brought into contact with the surface of the excavation for the purpose of minimizing those irregularities existing in the lower surface of the excavated channel after its formation. It is the purpose of roller 4 to eliminate such sharp upward projections in the lower surface of the excavation as would penetrate the membrane subsequently placed in the excavation.

As will be seen in FIG. 3, successively placed membranes are placed with their adjacent edges in overlapping relationship, thus forming in effect a continuous sheet of membrane over the area concerned. In order to insure the continuity of this sheet by insuring contact between adjacent edges, an adhesive material can be deposited along the upper side of the edge of that film whose edge assumes the underlying position to the placement of the subsequent film or, an adhesive can be deposited along the lower side of the edge of that film whose edge assumes the overlying position in the laying of the subsequent film. The latter is preferable inasmuch as it minimizes the likelihood of the adhesive layer being contaminated with particulate soil in the replacement step. Any suitable adhesive can be employed for effecting the sealing between adjacent sheets.

In completing the laying of this barrier it is a simple matter to lay the final membrane with its one edge overlapping the previously-placed membrane in the usual manner and its outer edge turned up in conformity to the ex cavation. Hence, there will be completed the installation of an enclosed water barrier.

It will be appreciated that various modifications can be made to the method of this invention. It is believed, however, that such are within the skill of the art in view of the foregoing disclosure.

What is claimed is:

1. A method of placing a substantially continuous moisture barrier at a substantially uniform distance beneath the surface of the soil which comprises:

(a) forming a first excavation by removing the soil to a substantially uniform depth and of a width lesser than the width of an after-defined membrane deposited therein;

(b) depositing across the width of said first excavation a membrane having one substantially vertically upstanding side wall, said membrane being deposited at a substantially uniform elevation across its width;

(0) depositing over a portion of the width of said first membrane the soil removed in forming the first excavation;

(d) forming successive excavation, each of which is in lateral contiguous relationship to a previously-formed excavation and has a width substantially equal to the width of said first excavation;

(e) depositing across the width of each successivelyformed excavation a membrane in lateral contact with the membrane of the previous excavation, said membrane being deposited at a substantially uniform elevation across their widths, the last of said membranes having one substantially vertically upstanding wall;

(f) depositing upon each of said successively-deposited membranes over a portion of its width, the soil removed in forming the excavation; and,

(g) closing the excavation.

2. The method as defined in claim 1 in which overlapping edges of successively-deposited membranes are in adhesively-sealed relationship.

3. The method as defined in claim 1 in which successive membranes are overlapped at their adjacent edges from about 2 to about 4 inches.

4. The method as defined in claim 1 in which the excavationed surface is smoothed and compressed prior to the deposition of the membrane.

References Cited UNITED STATES PATENTS 1,803,838 5/1931 Carpenter 61-72.6 X 2,160,462 5/ 1939 Schiferstein 9448 2,943,583 7/1960 Ryan 61-72.6 3,109,354 11/1963 Van Kirk 9448 X 3,309,875 3/1967 Niederwemmer 61-1 OTHER REFERENCES Excavating Engineer of August 1960, pp. 26-27.

JACOB SHAPIRO, Primary Examiner US. Cl. X.R. 61-1, l1, l3 

